1. Field of the Invention
The present invention relates to an image forming apparatus. In particular, the present invention relates to an image forming apparatus connected to a network and having power-supply control for power saving mode by which power consumption is reduced.
2. Description of the Related Art
As a printing technique, it has been known to transmit data (job) from a communication terminal (e.g. personal computer or PC) to one of a plurality of image forming apparatuses (e.g. printers, facsimile machines, multifunction peripherals) connected on a network so as to produce prints.
In such a case that a user on the network sends from the communication terminal an instruction to make prints, it is often desirable to select and use, from the image forming apparatuses on the network, an image forming apparatus that can produce and provide prints in the shortest period of time.
In order to select such an image forming apparatus, information is necessary as to whether or not the image forming apparatuses are each ready to make prints and whether or not there remain sufficient supplies, for example, paper. Then, a management information base (MIB) can be used for obtaining such information.
Regarding a power-saving structure of a facsimile machine, Japanese Laid-Open Patent Publication No. 11-27439 discloses a technique according to which supply of electric power to a block including a transfer unit, a scanner unit and a fan motor unit is shut off in power saving mode and a CPU detects any change of paper or a toner for example by a user.
If the technique disclosed in Japanese Laid-Open Patent Publication No. 11-27439 is employed, a problem arises that conditions of the image forming apparatus cannot be known via the network in power saving mode and thus it cannot be known when the image forming apparatus will be ready again to operate.
A management device has also been known that informs a service center of the status of an image forming apparatus via a network.
This type of management device immediately informs the service center of any trouble when it occurs in the image forming apparatus and then operates to shorten, as much as possible, the period in which the image forming apparatus is out of order. However, the image forming apparatus in power saving mode cannot inform the service center of status values or troubles for example. Therefore, the known techniques cannot provide immediate services addressing any trouble occurring in power saving mode.